Question

What is the factored form of the expression?

120y^2 – 63y – 147

Answer 1

3(5y - 7)(8y + 7 )

Explanation:

120y^2 – 63y – 147

Factor out a 3

3(40y^2 -21y -49)

40 = 1*40, 2*20 4*10 5*8

49 = 1*49 and 7*7

We need to play with the combinations to get -21 when added together

I will try

3(5y 7)(8y 7 )

We need the bigger one to be negative

5*7 + -8*7 = 35-56 = -21

So the 7 that multiplies by the 8 must be negative

3(5y - 7)(8y + 7 )